Umm... Hammer, If you notice, I did agree with you that Ogryns cannot ride in Valkyries. Canonically, they do ride in the backs of Taurus' and other open topped vehicles such as Gorgons as they can't ride in any closed topped vehicle due to a natural Claustrophobia that they all develop, which is why they never used to be able to ride in Chimera's or Valkyries, which, looking at my 6th edition codex, it looks as though this has been reconnected as they can now take a Chimera as a dedicated transport.

Also, he's not an Ogryn. He's a Minotaur... Not much difference in them, i'll grant you, it's just one has hooves and is a lot uglier.

As for Piloting... Well, Taurtacus doesn't know what the controls of an aircraft look like, much less fit into the cockpit and then fly it. Yoheved, as an Inquisitor is trained in the piloting of several light vehicles that are used for travelling great distances at speed such as Bikes/Jetbikes, Sentinels and Land Speeders. Therefore, if push came to shove, she'd probably have a fair go at piloting something like a Valkyrie, but don't expect a smooth ride... or a for the Valkyrie in question to be used by anyone else afterwards...